Abstract

SUMMARY

A family with type I dysgammaglobulinemia is presented in which a brother and sister were affected. These patients differ from those previously reported to have type I dysgammaglobulinemia on a congenital basis in that no antibody deficiency syndrome has appeared to date. Both, however, complained of frequent minor respiratory infections, perhaps as the result of absent secretion of respiratory immunoglobulin (Ig) A. This is the first time a family has been definitely proved to have more than one member affected. One of these was subjected to considerable immunologic testing, and some differences from expected normal behavior were demonstrated.

It is postulated that there are at least two genetic mechanisms that can result in type I dysgammaglobulinemia. Both of these are probably autosomal recessive traits and closely related but obviously are genetically distinct from classic agammaglobulinemia. One form results in a decrease in the rate of synthesis of specific heavy chains (alpha and gamma) and a compensatory increase of competent IgM, thus usually preventing an antibody deficiency syndrome. Such patients may, however, develop infections or other immunologic complications as a result of having to rely on only one type of antibody. The other form is manifested by an additional failure to produce competent antibody molecules and results in an antibody deficiency state.